Current electronic timepieces having a date display means such as a date dial require, to realize a perpetual calendar, that displayed date be read at the end of each month to compare that date with the perpetual calendar stored in the electronic circuitry.
A date reading mechanism based on an optical means is known, as disclosed, for example, in Japanese Patent Laid-Open Publication No. Hei 3-160392. According to the disclosed means, reflectors are provided on the reverse of several dates on the date dial and each reflector is detected over four consecutive dates by advancing the date dial to read the last date.
However, because reflector detection is made while the date dial is stopped, the date dial must be advanced to read the last date, thereby requiring a complicated circuit. In addition, the disclosed means require a significant amount of time to read the last date.
It is therefore an object of the present invention to provide an electronic timepiece having a device for automatically adjusting month-end calendar dates that allows quick and secure date recognition with a simple circuit.